Systems and methods increased mobility among mobile nodes in a wireless network

ABSTRACT

An apparatus, comprising a first router to communicatively couple to a mobility anchor point and one or more further routers to n-cast data items to ones of a plurality of mobile nodes that are experiencing similar radio propagation conditions.

TECHNICAL FIELD

Various embodiments described herein relate generally to mobile nodes ina wireless network and more particularly to systems and methods toincrease mobility of those mobile nodes.

BACKGROUND

Wireless devices are a ubiquitous part of every user's daily life.Through either a cell phone, Wireless Fidelity (Wi-Fi) capable laptop,or wireless enabled Personal Digital Assistant (PDA), a user may bewirelessly connected to a wireless network continually. However, theuser rarely remains fixed in location. The user continually moves aboutthe network. As the user moves about the network, his or her device mayrequire manual reconfiguration with every network change in the worstcase, or the user may experience a momentary loss of connection as thedevice reconfigures itself in the best case. In the latter situation, ifthe user is using services requiring high Quality of Service (QoS), theuser will experience a less than pleasing user experience.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIG. 1A is a network of wireless interconnected mobile nodes accordingto embodiments of the present invention;

FIG. 1B is a network of wireless interconnected mobile nodes accordingto embodiments of the present invention;

FIG. 2 is a high level block diagram of a system according toembodiments of the present invention;

FIG. 3 is a flowchart of a method according to embodiments of thepresent invention;

FIG. 4 is a flowchart of a method according to embodiments of thepresent invention; and

FIG. 5 is an example dataflow diagram according to embodiments of thepresent invention.

DETAILED DESCRIPTION

In the following detailed description of embodiments of the invention,reference is made to the accompanying drawings which form a part hereof,and in which are shown, by way of illustration, specific preferredembodiments in which the subject matter may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice them, and it is to be understood that otherembodiments may be utilized and that logical, mechanical, and electricalchanges may be made without departing from the spirit and scope of thepresent disclosure. Such embodiments of the inventive subject matter maybe referred to, individually and/or collectively, herein by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept if more than one is in fact disclosed.

This application refers herein to certain Request for Comments (RFC) asdefined by the Internet Engineering Task Force (IETF) and the InternetEngineering Steering Group (IESG) which are recorded and published asstandards track RFCs. Request for Comment 3775 (D. Johnson, C. Perkins,J. Arkko, “Mobility Support in IPv6,” RFC 3775, published June, 2004)specifies a protocol which allows nodes to remain reachable while movingaround in the Internet based on Internet Protocol Version 6 (IPv6).Request for Comment 2461 (T. Narten, E. Nordmark, W. Simpson, “NeighborDiscovery for IP Version 6 (IPv6),” RFC 2461, published December 1998)specifies the Neighbor Discovery protocol for IPv6. IPv6 nodes on thesame network use Neighbor Discovery to discover each other's presence,to determine each other's link-layer addresses, to find routers and tomaintain reachability information about the paths to active neighbors.Request for Comment 2462 (S. Thomson, T. Narten, “IPv6 Stateless AddressAutoconfiguration,” RFC 2462, published December 1998) specifies thesteps a host takes in deciding how to autoconfigure its interfaces inIPv6.

Reference is also made herein to the proposed specification forHierarchical Mobile IPv6 (HMIPv6). HMIPv6 is being finalized by theMobile IPv6 Signaling and Handoff Optimization (mipshop) working groupof the IETF and deals with reducing the amount and latency of signalingamongst a mobile node, its home agent and one or more correspondents byintroducing a mobility anchor point (e.g., a special node located in thenetwork visited by the mobile node). In the proposed specification, themobility anchor point acts somewhat like a local home agent for thevisiting mobile node by limiting the amount of signaling requiredoutside the mobility anchor point's domain. The HMIPv6 proposedspecification is currently an Internet Draft and has not yet beenadvanced to the standards track and RFC status. The current version ofthe HMIPv6 Internet-Draft, published December 2004, and which expires inJune 2005, can be found athttp://www.ietf.org/internet-drafts/draft-ietf-mipshop-hmipv6-04.txt. Asexplained in the Guidelines to Authors of Internet-Drafts, available athttp://www.ietf.org/ietf/1id-guideliries.html, last updated on Mar. 25,2005, Internet-Drafts are draft documents valid for a maximum of sixmonths and may be updated, replaced, or obsoleted by other documents atany time. References herein to the HMIPv6 Internet-Draft are madetherefore for informational purposes since it is understood that theHMIPv6 Internet-Draft is a work in progress.

“Data items” as used in the present discussion may include, withoutlimitation: wireless data signals, network packet data, network signals,etc. Wireless data signals may include, without limitation, signals inaccordance with one or more of the following standards: Global Systemfor Mobile Communications (GSM); General Packet Radio Service (GPRS);Code Division Multiple Access (CDMA); Time Division Multiple Access(TDMA); IEEE 802.11 standard signals, IEEE std. 802.11-1999, published1999 and later versions (hereinafter IEEE 802.11 standard); IEEE 802.16standard signals, IEEE std. 802.16-2001, published 2001 and laterversions (hereinafter IEEE 802.16 standard); IEEE 802.15 standardsignals, IEEE std. 802.15.1-2003, published 2003, IEEE 802.15.2-2003,published 2003, IEEE 802.15.3-2003, published 2003 and later versions(hereinafter IEEE 802.15 standard); Wide Band CDMA (WCDMA); High SpeedDownlink Packet Access (HSDPA); or Ultra WideBand (UWB). Though specifictypes of wireless signals are listed above, for the embodiments hereinit is to be appreciated that any signal that passes between two deviceswithout a wire is considered to be a wireless signal. Though mention ismade here to wireless signals, the systems and methods described hereinapply equally to wired as well as wireless networks in the context ofrouter to router communications.

The term “router” as used herein is meant to denote any device on anetwork configured to receive data items addressed to other devices onthe network and forward those data items to the appropriate device usingany suitable communications protocol.

FIG. 1A is a network of wireless interconnected mobile nodes accordingto embodiments of the present invention. In an embodiment, a network 100includes a mobility anchor point (MAP) device 102, one or more overlaprouter devices (OR) 104, one or more access router devices (AR) 106 andone or more mobile node devices (MN) 108. In an embodiment, data signalsare communicated between any or all of the devices on the network 100.

In an embodiment, the MAP 102 is a device located in the network 100accessible by one or more MNs 108. Accessible, includes, withoutlimitation the ability of a MN 108 to communicatively connect to andbegin transmitting data items to and receiving data items from ARs 106on the network 100, and through the ARs 106 and other devices on thenetwork, the MN 108 is capable of transmitting and receiving data itemsto and from the MAP 102. In an embodiment, the MAP 102 is used by theone or more MNs 108 as a local home agent (HA). The MAP 102 as a localHA for the one or more MNs 108 allows seamless connectivity for the oneor more MNs 108 as the MNs 108 move around in the network 100. Thoughdepicted as a single device in FIG. 1A, it is understood that there canbe more than one MAP 102 in any given network.

In an embodiment, the ARs 106 are devices on the network accessible toone or more MNs 108. In an embodiment, each of the ARs 106 is configuredto be a default router for one or more MNs 108. Each of the ARs 106 isfurther configured to aggregate the outbound traffic or data items fromthe one or more MNs 108 to the network 100.

In an embodiment, the MNs 108 are devices, such as, without limitation,computers, mobile phones, or PDA's, configured to communicate wirelesslywith at least one AR 106 using MIPv6 as the network protocol. MIPv6 asdescribed in RFC 3775 and HMIPv6 as described in the proposedspecification provide a network structure in which a MN 108 can moveabout the network 100 and still maintain a network connection. As the MN108 moves from a communicative connection with a first AR 106 to asecond AR 106, the network 100 is configured to handoff communicationsfrom the first AR 106 to the second AR 106. Through this operation, mostdata items addressed to and coming from the MN 108 are delivered totheir intended recipient.

Using FIG. 1A as a reference, operations of the MNs 108 as theycommunicate with the network 100 can be discussed. In an embodiment, asa MN 108 enters the network 100 and begins to communicate with an AR106, it is configured to detect the presence of a MIPv6 network and sendan initial local binding update (LBU) to the MAP 102 and the MAP 102 isconfigured to operate as the HA for the MN 108 and configure a RegionalCare of Address (RCoA) for the MN 108. The RCoA of the MN 108 is anetwork address that devices outside the network 100 can use forcommunications with the MN 108 without needing to know the exact networkaddress of the MN 108. The RCoA further allows the MN 108 to move fromcommunicating with one AR 106 to any other AR 106 without a change inits RCoA, requiring no configuration change with a host outside thenetwork that the MN 108 may be communicating with during that move. Dataitems received by the MAP 102 addressed to the RCoA of the MN 108 areforwarded to the MN 108 as outlined in MIPv6 and in the presentdiscussion. As the MN 108 moves from communicating with one AR 106 toanother AR 106, it is further configured to send additional bindingupdates to the MAP 102.

In an embodiment, the OR 104 is a device configured to receive dataitems from the MAP 102 that are addressed to a MN 108. In a furtherembodiment, the OR 104 is further configured to read a hop-by-hopextension option in the header of the data item and forward the dataitem based on that option. In one embodiment, the OR 104 is a separatedevice. In another embodiment, the functionality of the OR 104 may becontained either in an AR 106 or the MAP 102. Such an arrangement may beadvantageous and allow the network 100 to maintain operations if one ormore, but not all, devices on the network 100 fail.

In an embodiment, a MN 108 communicating with an AR 106 is assigned to adedicated subnet specific to that AR 106. All network traffic receivedby the MAP 102 addressed to the RCoA of the MN 108 is re-addressed withthe subnet prefix of the AR 106 with which the MN 108 is communicating.In one embodiment, the subnet prefix changes as network operations arehanded off from one AR 106 to another AR 106. In such an arrangement,any additional network traffic received by the MAP 102 addressed to theRCoA of the MN 108 is re-addressed to the new subnet prefix.

A MN 108 can experience similar radio propagation conditions from morethan one AR 106. In the context of the above discussion, the MN 108maintains communications with only one of the ARs 106. Only when the MN108 moves or the AR 106 it is communicating with ceases to send andreceive network traffic, does the MN 108 hand off network operations tothe other AR 106. This creates a hand-off period during which importantdata can be lost.

In an embodiment, the MN 108 is configured to send measurement reportsto the AR 106 when first associating with the AR 106. The MN 108 isfurther configured to send a measurement report when any change in thequality of the link between the MN 108 and any AR 106 that the MN 108can communicate with is detected. If the MN 108 is communicating withmore than one AR 106, the measurement report is sent to only one AR 106.In an embodiment, the measurement report is a report detailing the radiolink quality between the MN 108 and an AR 106. In a further embodiment,the measurement report contains, without limitation, a set of tuples,comprising: access network identity, and signal quality/strength. In oneembodiment, the measurement report is sent to the AR 106 usingunderlying Layer 2 mechanisms as outlined in the Open SystemInterconnection (OSI) Network Model. In another embodiment, themeasurement report is sent using a Router Solicitation message asdefined by RFC2461. As provided for in RFC 2461, Router Solicitationmessages are messages that request routers to generate a responseimmediately. In such an arrangement, the measurement report alsocomprises information additional to the standard Router Solicitationmessage as described in RFC 2461.

In an embodiment, ARs 106 are configured to receive the measurementreport from a MN 108 and prepare an advertisement message based on thereceived measurement report. In an embodiment, the advertisement messageis a message from the AR 106 to the MN 108 providing informationregarding network access, including, but not limited to, subnet prefixassignments. The AR 106 maintains a local database and is configured tocompare the received measurement report with data in the local database.In an embodiment, the records in the local database may contain, withoutlimitation, information regarding: access network identity; signalquality threshold with respect to the link between a MN 108 and an AR106; and associated IPv6 subnets. In a further embodiment, overlapsubnets may be advertised. Overlap subnets are a subset of regular IPv6subnets. In an embodiment, and IPv6 subnet is an overlap subnet if thereexists another (or many other) subnet(s) that can be used to communicatewith the MN 108 with similar link quality. In an embodiment, theassociation between overlap subnets is maintained in the OR 104.

The MN 108 is capable of auto-configuring its IPv6 address as outlinedin RFC 2462. In an embodiment, the MN 108 is further configured toautoconfigure new IP addresses belonging to all assigned overlap subnetprefixes when an advertisement message is received containing overlapsubnet prefixes. The MN 108 is configured to use the same interfaceidentifier on all overlap subnets. In a further embodiment, the MN 108is further configured to send a Local Binding Update (LBU) to the MAP102 to register the new RCoA which is the auto-configured IPv6 addressfrom the one or more overlap subnets. In such an arrangement, the MAP102 is further configured to tunnel packets to the RCoA registered bythe MN 108. In an embodiment, the MAP 102 is configured to construct apacket with an outer packet header followed by a hop-by-hop extensionoption and initiate the hop-by-hop extension option to zero. In afurther embodiment the hop-by-hop extension header may carry aMultihoming in Overlap Subnets for IP Micro-mobility Robustness(MUHOMOR) hop-by-hop option.

FIG. 1B is a network of wireless interconnected mobile nodes accordingto embodiments of the present invention. FIG. 1B is similar to FIG. 1Awith the addition of specific references to the relationship betweenmultiple devices communicating on the network 100.

In an embodiment, when a MN 108 is able to communicate with two or moreARs 106, all of the ARs 106 are configured to include subnet prefixinformation for each of the two or more ARs 106 in any advertisementmessage sent to the MN 108. In such an arrangement, using FIG. 1B as anexample, MN1 108 areceives an advertisement message with the A1 110subnet prefix only when measuring a good link with AR1 106 a. Ifreceiving a good signal from the AR2 106 b, the MN2 108 b receives anadvertisement message with the B1 112 subnet prefix. In the case of theMN3 108 c, which is measuring a good link with both the AR1 106 a andthe AR2 106 b, the advertisement message contains both the A2 114 and B2116 subnet prefixes.

FIG. 2 is a high level block diagram of a device according toembodiments of the present invention. In an embodiment, the device is anOR 104 as contemplated above with respect to FIG. 1A. In an embodiment,the OR 104 comprises a MUHOMOR module 210 and a network interface 212.In another embodiment, the OR 104 is operably coupled to an antenna 214.The antenna 214 may include one or more of a patch, omni-directional,beam, monopole, dipole, and rhombic antenna, among others. Though theantenna 214 depicted as external to the OR 104, it is understood thatthe antenna 214 may be integral to the OR 104 and such depiction is notto be taken in any limiting way. In another embodiment, the AR 106 isoperably coupled to an antenna similar to the antenna depicted in FIG. 2and described here. Additionally, the OR 104 is coupled to a wirelessnetwork 220. The wireless network 220 includes one or more ARs 106 andone or more MNs 108.

In an embodiment, the MUHOMOR module 210 is configured to receive dataitems addressed to a MN 108, read a configurable option in the data itemand process the data item based on the configurable option in the dataitem. In an embodiment, the configurable option is a MUHOMOR option. Inone embodiment, the MUHOMOR module 210 n-casts the data item to the MN108 if the MUHOMOR option is set to a non-zero value. In such anarrangement, the MN 108 is configured to multihome on several subnetsconcurrently and receive n-cast data items sent from the OR 104.“Multihoming” as used herein is a MN's 108 ability to have multiplenetwork addresses in one computer, usually on different networks. In anembodiment, the MAP 102 is configured to insert the configurable optionin each data item received by the MAP 102 addressed to the RCoA of a MN108. In another embodiment, the MAP initializes the configurable optionto zero when inserting the configurable option.

FIG. 3 is a flowchart of a method that could be carried out on a devicesuch as those depicted in FIG. 1A and FIG. 2, according to embodimentsof the present invention. In one embodiment, the operations described inFIG. 3 are carried out in an AR 106 as depicted in FIG. 1A. In a furtherembodiment, the functions of the AR 106 and the OR 104 are combined in asingle device. In such an arrangement, the operations described here canbe carried out on that single device.

At block 310, the device receives a report from one or more mobilenodes, such as the MN 108 depicted in FIG. 1A. In an embodiment, thereport is a measurement report detailing the radio propagationconditions that the MN 108 is experiencing with respect to the AR 106.In another embodiment, the measurement report contains information withrespect to all ARs 106 that the MN 108 can communicate with. In afurther embodiment, the measurement report is a report regarding theradio propagation conditions that the MN 108 is experiencing withrespect to the ARs 106 that it can communicate with.

At block 315, the device compares data in the received report with datastored in a local database. Records in the local database can include,without limitation, access network identity, signal quality thresholdand associated IPv6 subnets. In an embodiment, the device compares thelink quality reported by the MN 108 with at least one AR 106, and thesignal quality threshold contained in the record for the at least one AR106. In another embodiment, the device compares the link qualityreported by the MN 108 with the signal quality threshold for each of theARs 106. In such an example, if the link quality exceeds the signalquality threshold of any of the ARs 106, the MN 108 has a good link witheach of those ARs 106.

In another embodiment, the device compares some other value contained inthe measurement report and compares that value with similar data storedin the local database to determine if the some other value exceeds athreshold value for that type of measurement. If it is determined thatit does, the MN 108 is determined to have a good link. In such anexample, the device determines if the MN 108 has a good link with any ofthe ARs 106 based on that comparison. In an embodiment, the deviceassigns one or more subnet prefixes from a group of subnet prefixesassociated with each of the ARs 106 that the MN 108 has a good linkwith. In such an arrangement, the device assigns the one or more subnetprefixes to the MN. If the MN 108 has a good link with only one AR 106,a single subnet prefix is chosen. If the MN 108 has a good link withmore than one AR 106, more than one subnet prefix is chosen. In anembodiment, when more than one subnet prefix is assigned to a MN 108,the MN 108 is configured to receive data items addressed to each of thesubnet prefixes.

At block 320, the device generates an advertisement message based on thecomparison. In an embodiment, the advertisement message contains theassigned subnet prefix as discussed above. At block 325 the device sendsthe advertisement message to the MN 108 from which it received thereport. In an embodiment, if the MN 108 has a good link with only one AR106, the advertisement message contains one subnet prefix. The MN 108receives the advertisement message and broadcasts a LBU message to theMAP 102 with that subnet prefix and the RCoA of the MN 108. Furthernetwork traffic addressed to the RCoA of the MN 108 is re-addressed tothis subnet prefix and forwarded using standard IPv6 forwarding methods.

In an embodiment, if the MN 108 has a good link with more than one AR106, the device receiving the measurement report generates anadvertisement message containing the subnet prefixes of all ARs 106 withwhich the MN 108 has a good link. The subnet prefixes described here aresubnet prefixes assigned to the MNs 108 that are experiencing similarlink quality conditions with two or more ARs 106 such that networktraffic addressed to the RCoA of the MNs 108 can be handled differentlythan network traffic addressed to a MN 108 communicating with only asingle AR 106. The MN 108 receives this advertisement message andauto-configures new IPv6 addresses belonging to all assigned subnets.The MN 108 sends an LBU message to the MAP 102 and all network trafficaddressed to the RCoA of the MN 108 is re-addressed to the assignedsubnets.

With reference to FIG. 1B, an exemplary situation can be described withrespect to block 315 of FIG. 3. In FIG. 1B, the measurement report sentby MN3 108 c contains information related to the link quality of boththe link to the AR1 106 a and the AR2 106 b. The measurement report maybe sent to either the AR1 106 a or the AR2 106 b as the MN3 108 c has acommunicative connection with both the AR1 106 a and the AR2 106 b. TheAR receiving the report, compares the report to its local database anddetermines that the MN3 108 c has a good link with both the AR1 106 aand the AR2 106 b. The advertisement message sent to the MN3 108 ccontains the subnet prefixes for both the AR1 106 a and the AR2 106 b,allowing the MN3 108 c to auto-configure using the both subnet prefixesand send the LBU to the MAP 102. The MAP 102 then registers the RCoA ofthe MN3 108 c and re-addresses all packets addressed to the RCoA withboth the subnet for the AR1 106 a and the AR2 106 b and sends thatpacket downstream towards the MN3 108 c through both the AR1 106 a andthe AR2 106 b.

At block 320, data items addressed to mobile nodes assigned to more thanone subnet are n-cast to all subnets assigned to the mobile node. Withreference to the discussion above in regards to the MN3 108 c, dataitems addressed to the RCoA of the MN3 108 c is n-cast to the twosubnets assigned to the MN3 108 c. As will be understood by thoseskilled in the art, this is the simple case. In other embodiments, a MN108 may experience similar radio propagation conditions or a good linkfrom more than two access routers. In such an arrangement, the dataitems addressed to the RCoA of the MN 108 are n-cast to all subnetprefixes assigned to the MN 108.

FIG. 4 is a flowchart of a method according to embodiments of thepresent invention. In one embodiment, the operations described in FIG. 4are carried out in an OR 104 as depicted in FIG. 1A and FIG. 2. Inanother embodiment, the operations described are carried out in a MAP102 as depicted in FIG. 1A and FIG. 2. In yet another embodiment, theoperations are carried out in an AR 106 as depicted in FIG. 1A. In afurther embodiment, functions of the AR 106, OR 104 or MAP 102 arecombined in a single device. In such an arrangement, the operationsdescribed in FIG. 4 are carried out in that single device.

At block 410 the device receives data items addressed to a MN 108. Atblock 415, the device determines if the MN 108 is in an overlap subnet.If the MN 108 is not in an overlap subnet, the data item is forwarded tothe MN 108 using standard forwarding at block 420. Standard forwardingincludes, without limitation, IPv6 forwarding. If the MN 108 is in anoverlap subnet, operations continue at block 425.

At block 425, the device reads a configurable option in the header ofthe data item. In an embodiment, the configurable option in the headerof the data item includes a hop-by-hop extension header. In oneembodiment, the configurable option includes a MUHOMOR hop-by-hopextension header. If the configurable option is set to a non-zero value,the data item is forwarded using standard IPv6 forwarding at block 420.If the configurable option is set to a zero value, the device sets theconfigurable option to a non-zero value at block 430. In an embodiment,the configurable option is set to the value of a global countermaintained by the device. In a further embodiment, the global counter isincremented. In such an arrangement, the global counter must skip zerowhen the counter flips to zero.

At block 435, the data item is replicated n-times and each of thereplicated data items is forwarded to each of the subnet prefixesassigned to the MN 108 to which the data item is addressed. In a casewhere the MN 108 is assigned two subnet prefixes, the data item isduplicated. In an embodiment, a non-zero value in the MUHOMOR hop-by-hopextension header allows for redundancy among overlap routers in that anoverlap router downstream of the first overlap router is stillconfigured to perform the operations outlined here, but only when theupstream overlap router fails will the downstream overlap router n-castthe received data items.

In an embodiment, each device in the network 100 depicted in FIG. 1 thatreceives data items addressed to mobile nodes and sends those data itemsis configured to read the configurable option as outlined above. In suchan arrangement, downstream ARs 106 are configured to handle operationsnormally performed by the upstream OR's 104 if such upstream OR's 104fail. In a further embodiment, the functions of the OR 104 are containedin the MAP 102, such that the MAP 102 is configured to not only receiveand send data items as outlined in RFC 3775, but to also read theconfigurable option and perform the operations outlined above.

FIG. 5 is an example dataflow diagram according to embodiments of thepresent invention. A first network packet 502 is received by a MAP 102.The first network packet 502 is addressed to the RCoA of a MN 504. Forthe purposes of the example dataflow diagram in FIG. 5, it is to beassumed that the MN 504 has a good link with both the AR1 106 a and theAR2 106 b.

The MAP 102 is configured to receive the first network packet 502 andtunnel the packet 502 to the RCoA of the MN 504, wrapping an outer IPv6header followed by the hop-by-hop extension header carrying the MUHOMORhop-by-hop option as outlined above around the received first networkpacket 502. The option would carry a counter that the MAP 102 wouldinitiate to 0, as shown in the second network packet 506.

The second network packet 506 is received by an OR 104 and the MUHOMORoption is read. In this case, the received packet 506 contains a zerovalue in the MUHOMOR option of the packet header as initiated by the MAP102 and the MN 504 has a good link with both the AR1 106 a and the AR2106 b. As discussed above, a determination as to which access routerthat a mobile node has a good link with is performed by comparing anydata indicative of link quality in a measurement report received from amobile node with similar data indicative of link quality contained in alocal database accessible to the access router Examples of such dataindicative of link quality include, without limitation, signal to noiseratio, signal strength, noise level, number of devices communicatingwith the access router, and the like. A good link is an indication thatthe mobile node is experiencing an acceptable communicative connectionwith the access router and data items can be transmitted from the accessrouter to the mobile node with a high probability of successfuldelivery.

As discussed above with respect to FIG. 4, had the MN 504 not been in anoverlap subnet, the received packet would have been forwarded usingstandard IPv6 forwarding, however in the present example; furtherprocessing is required as the MN 504 is in an overlap subnet. As the MN504 is in an overlap subnet, the OR1 104 a inserts a non-zero value intothe MUHOMOR option of the network packet 506. Following insertion of anon-zero value into the MUHOMOR option of the network packet, the OR1104 a duplicates the network packet in this case, replicates n-times inthe general case, and sends those network packets to the appropriateoverlap subnets. For the packets addressed to the AR1 106 a subnet, thepackets contain the AR1 106 a overlap subnet prefix (A2 in FIG. 5), anon-zero value of 8 in this example in the MUHOMOR option and the datacontained in the first network packet as shown in network packet 508.For the packets addressed to the AR2 106 b subnet, the packets containthe AR2 106 b subnet prefix (B2 in FIG. 5), a non-zero value of 8, inthis example, in the MUHOMOR option and the data contained in the firstnetwork packet as shown in network packet 510.

Between OR1 104 a and AR1 106 a, there is an additional overlap router,the OR2 104 b. The OR2 104 b receives the network packet in the samemanner as the OR1 104 a. In the example of FIG. 5, the OR2 104 bdetermines that the MN 504 the network packet 508 is addressed to isexperiencing similar radio propagation conditions from both the AR1 106a and the AR2 106 b. The OR2 104 b reads the MUHOMOR option in thenetwork packet 508, determines that it contains a non-zero value of 8 inthis example and forwards the packet using standard IPv6 forwarding asshown in network packet 512. A second overlap router, as outlined inthis example, provides for redundancy in the event that the OR1 104 afails. Additionally, if all upstream ORs fail, it is advantageous if theAR communicating with the MN 504 has the option of performing the sameoperations. The AR1 106 a receives the forwarded packet 512 from the OR2104 b and forwards the packet 514 to the MN 504. Further, in thesituation where multiple overlap routers are present the MUHOMOR optionensures that the network packet is only processed once by an overlaprouter using the methods discussed here, preventing loops in networkoperations.

For packets addressed to the B2 overlap subnet prefix of the AR2 106 b,the AR2 106 b receives the network packet 510 addressed to the B2 subnetprefix and forward that network packet 516 to the MN 504.

The MN 504 in this example receives duplicate packets containing thesame data. The MN 504 is configured to multihome on both the A2 subnetand the B2 subnet concurrently. Any method suitable to provide formultihoming on a mobile node can be used as are well known in the art,and are considered to be within the scope of the present discussion.

Thus, although specific embodiments have been illustrated and describedherein, it should be appreciated that any arrangement calculated toachieve the same purpose may be substituted for the specific embodimentsshown. This disclosure is intended to cover any and all adaptations orvariations of various embodiments of the invention. Combinations of theabove embodiments and other embodiments not specifically describedherein will be apparent to those of skill in the art upon reviewing theabove description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b), requiring an abstract that allows the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. Additionally, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments of the invention require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separate preferred embodiment. In the appendedclaims, the terms “including” and “in which” are used as theplain-English equivalents of the terms “comprising” and “wherein,”respectively. Moreover, the terms “first,” “second,” and “third,” etc.are used merely as labels, and are not intended to impose numericalrequirements on their objects.

1. An apparatus, comprising: a network including an overlap routercommunicatively coupled to a mobility anchor point and to a plurality ofaccess routers, each of the plurality of access routers including alocal database and having a different subnet prefix address, each of theplurality of access routers is configured to receive one or moremeasurement reports from one or more mobile nodes including informationwith respect to which of the plurality of access routers a given mobilenode can have communication with; each of the access routers isconfigured to compare received measurement reports to one or morethresholds stored in the local database coupled to the access router,and to communicate to the given mobile node an advertisement messagesincluding a subnet prefix of each of the plurality of access routersthat the given mobile node has a good communication link with based onthe received one or more measurement reports; the mobility anchor pointis configured to be communicatively coupled to any of the given mobilenodes through one or more of the plurality of access routes and throughthe overlap router, the mobility anchor point is configured to be alocal home agent for each of the given mobile node and to receive fromeach of the given mobile nodes a local binding update and a listing ofall of the subnet prefixes for which the given mobile node has a goodcommunication link established with, the mobility anchor point isconfigured to configure a Regional Care of Address for the given mobilenode, the Regional Care of Address information is configured to allowone or more devices outside the network to have communication throughthe mobility anchor point with the given mobile node associated with theRegional Care of Address without having to know any of the subnetprefixes assigned to the given mobile node; the overlap router isconfigured to receive data items addressed to the Regional Care Addressof a particular mobile node, to re-address the data to include any ofthe at least one subnet prefixes sent to the mobility anchor point forthe particular mobile node, and to n-cast the data items to all of theplurality of access routers that have subnet prefixes assigned to theparticular mobile node.
 2. The apparatus of claim 1, wherein the overlaprouter is to n-cast the data items to more than one of the plurality ofaccess routers.
 3. The apparatus of claim 1, wherein the overlap routerincludes a MUHOMOR module, and is to n-cast the data items only to onesof the access routers that are experiencing communications with theparticular mobile node at a signal quality that exceeds a signal qualitythreshold using a configuration option that includes MUHOMOR option. 4.The apparatus of claim 1, wherein one or more of the one or more accessrouters is configured to communicate on at least of a WCDMA network or abroadband wireless access network.
 5. The apparatus of claim 1, whereinthe particular mobile node is configured to multihome.
 6. A methodcomprising: receiving a measurement report from a mobile node, themeasurement report containing information including the link qualitybetween the mobile node and one or more access routers that the mobilenode can have communication with; comparing data in the measurementreport with data stored in a local database coupled to the accessrouters to determine which of the access routers the mobile node has agood link with; assigning to the mobile node one or more subnetprefixes, each of the one or more subnet prefixes associated with one ofthe access routers that the mobile node has a good link with; generatingan advertisement message, where the advertisement message contains theone or more subnet prefixes assigned to the mobile node; sending theadvertisement message to the mobile node; transmitting from the mobilenode to a mobility anchor point coupled to the one or more accessrouters a local binding update and a listing of at least one subnetprefix included in the advertisement message sent to the mobile unit;configuring at the mobility anchor point a Regional Care of Address forthe mobile node; configuring the mobile node to receive data itemsaddressed to Regional Care of Address for the mobile node; receiving atthe mobility anchor point data items addressed to the Regional Care ofAddress for the mobile node; re-addressing the data items to includeaddresses for each of the subnet prefixes for the mobile node; andn-casting the re-addressed data items to all of the plurality of accessrouters that have subnet prefixes assigned to the particular mobilenode.
 7. The method of claim 6, wherein the data stored in the localdatabase includes information related to the one or more access routersin a wireless network accessible to the mobile node.
 8. The method ofclaim 6, wherein the data stored in the local database includes at leastsignal quality threshold data for the one or more access routers.
 9. Themethod of claim 8, wherein data in the measurement report includes datarelating to a link quality between the mobile node and the one or moreaccess routers.
 10. The method of claim 9, wherein comparing includescomparing the link quality data in the measurement report with thesignal quality data threshold for the one or more access routers. 11.The method of claim 10, wherein the advertisement message contains asingle subnet prefix if the link quality data exceeds the signal qualitythreshold data for one of the one or more access routers.
 12. The methodof claim 10, wherein the advertisement message contains more than onesubnet prefix if the link quality data exceeds the signal qualitythreshold data for more than one of the one or more access routers. 13.The method of claim 6, wherein the mobile node is to receive theadvertisement message and send to a mobility anchor point a localbinding update message containing the two or more subnet prefixes.
 14. Asystem, comprising: a network including an overlap routercommunicatively coupled to a mobility anchor point and to a plurality ofaccess routers, each of the plurality of access routers including alocal database and having a different subnet prefix address, each of theplurality of access routers is configured to receive one or moremeasurement reports from one or more mobile nodes including informationwith respect to which of the plurality of access routers a given mobilenode can have communication with; each of the access routers isconfigured to compare received measurement reports to one or morethresholds stored in the local database coupled to the access router,and to communicate to the given mobile node an advertisement messagesincluding a subnet prefix of each of the plurality of access routersthat the given mobile node has a good communication link with based onthe received one or more measurement reports; the mobility anchor pointis configured to be communicatively coupled to any of the given mobilenodes through one or more of the plurality of access routes and throughthe overlap router, the mobility anchor point is configured to be alocal home agent for each of the given mobile node and to receive fromeach of the given mobile nodes a local binding update and a listing ofall of the subnet prefixes for which the given mobile node has a goodcommunication link established with, the mobility anchor point isconfigured to configure a Regional Care of Address for the given mobilenode, the Regional Care of Address information is configured to allowone or more devices outside the network to have communication throughthe mobility anchor point with the given mobile node associated with theRegional Care of Address without having to know any of the subnetprefixes assigned to the given mobile node; the overlap router isconfigured to receive data items addressed to the Regional Care Addressof a particular mobile node, to re-address the data to include any ofthe at least one subnet prefixes sent to the mobility anchor point forthe particular mobile node, and to n-cast the data items to all of theplurality of access routers that have subnet prefixes assigned to theparticular mobile node; at least one network interface device coupled tothe overlap router; and at least one omni-directional antenna coupled tothe overlap router.
 15. The system of claim 14, wherein the at least onenetwork interface device is to communicate using Internet ProtocolVersion
 6. 16. The system of claim 14, further comprising a mobilityanchor point communicatively coupled to each of the access routersthrough the overlay router.
 17. The system of claim 14, wherein theoverlay router comprises a MUHOMOR module, the MUHOMOR module coupled tothe mobility anchor point and the network interface device, the MUHOMORmodule to received the data items and to n-cast the data items to theparticular mobile node through each of the plurality of access routersassociated with the subnet prefixes assigned to the particular mobilenode.